The invention is based on an apparatus for injecting a fuel-air mixture into an intake tube of a mixture-compressing internal combustion engine. German Patent Document 32 40 554 A1 (U.S. Pat. No. 4,545,354) has already disclosed an apparatus for injecting a fuel-air mixture that relates to a throttle tang-type injection valve with a gas guide element; the injection opening of the injection valve is surrounded, in the immediate vicinity of the gas guide element, by an annular gas gap communicating with an annular gas conduit. However, this apparatus has the disadvantage that because of production tolerances, the annular gas gap that meters the gas and is predetermined by engine requirements must be adjusted by displacement or bending of the gas guide element. Adapting the annular gas gap entails high costs in large-scale mass production of this known apparatus. Because of capillary action, the danger exists in the known apparatus that during operation without the delivery of gas, fuel may intermittently enter the annular gas conduit through the annular gas gap, so that when gas flow ensues, an undesirable enrichment of the fuel-air mixture can occur.